JP2005192475A - Method for producing frozen cooked rice, frozen cooked rice and thawing method for the frozen cooked rice - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing frozen cooked rice having puffy palate feeling and excellent flavor and taste of just cooked rice at the time of thawing and heating, and to provide the frozen cooked rice. <P>SOLUTION: The method for producing the frozen cooked rice comprises washing rice by a normal method in a rice washing process 11, soaking the rice in a soaking process 12 and steaming the rice in a steaming process 13, warming the rice in hot water at 80-100°C in a warming process 14 in hot water and boiling the rice to bring gelation degree to 80-90%. Furthermore, the method comprises quickly freezing the cooked rice thus obtained in a loose condition in a first freezing process 17, and coating water or seasoning liquid on the surface in a hydration process 18 followed by quickly freezing the rice in a loose condition in a second freezing process 19. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing frozen cooked rice that is thawed and heated in a microwave oven, a frozen cooked rice, and a method for thawing the same, and more specifically, cooking rice by thawing and heating rice that has been rapidly frozen (IQF) in a microwave. The present invention relates to a method for producing frozen cooked rice, a frozen cooked rice, and a thawing method thereof.

  Conventionally, in frozen rice that is thawed and heated in a microwave oven, various ideas have been made so that the cooked rice has the texture and flavor of freshly cooked rice.

For example, steaming cooked cooked rice with less water, watering the surface to absorb water, and then rapidly freezing in a rose shape, water flies from the cooked rice surface during frozen storage and thawing heating, and the cooked rice surface What prevents drying (see Patent Document 1), rice is cooked to a low degree of gelatinization, then water is evenly attached to the surface of the rice, then it is frozen in a rose shape and gelatinized when heated by thawing The rice is cooked in low temperature (see Patent Document 2). By spraying water on the surface of the cooked rice and then quickly freezing it in a rose shape, There is one that prevents drying (see Patent Document 3).
JP-A-1-256355 JP-A-6-237715 JP-A-3-254651

  However, in the thing of the above-mentioned patent document 1, since the rice cooked in the state which reduced the amount of water is added, and it immerses in water and freezes, it is very difficult to freeze rice in the shape of a rose, It was frozen in blocks. For this reason, the amount of water absorbed by the cooked rice during thawing heating increases, and furthermore, the thawing heating time becomes significantly longer, so that the state of the cooked rice after thawing heating deteriorates or the weight and thawing of the cooked rice before thawing There was a problem that a difference occurred in the weight of the later cooked rice. In addition, cooked rice frozen in a block shape has uneven temperature rise rates depending on the location of the block during thawing heating, and variation occurs in thawing heating, but it has been difficult to suppress this variation.

  Even the thing of patent document 2 attaches water to the surface of the cooked rice cooked in the state with a low gelatinization degree, and freezes it in the state which increased the moisture content, Therefore It is difficult to freeze cooked rice in rose shape. Moreover, in the thing of patent document 3, since water is sprayed and frozen on the cooked rice in the state fully cooked, the fragrance of freshly cooked cooked rice is lost, and texture and taste are also lowered. It was also difficult to freeze into a shape.

  Therefore, the present invention provides a method for producing frozen frozen rice in the form of roses that can obtain a fluffy texture of cooked cooked rice, a good aroma and taste at the time of eating after thawing heating, and frozen rice The purpose is to provide a method for the decompression. The term “rose rapid rapid setting” as used herein does not necessarily refer to a state in which each rice grain is separated and frozen, and even if several to several tens of rice grains are agglomerated, the thawing time and the required amount As long as there is no support for segregation, it is acceptable.

  In order to achieve the above object, the method for producing frozen cooked rice according to the present invention includes a rice cooking process in which raw rice is cooked in a state where the gelatinization degree is 80% to 96%, and the rice cooked through the rice cooking process is rapidly frozen in a rose shape. It includes a primary freezing step, a water adding step for coating water on the surface of cooked rice after the primary freezing step, and a secondary freezing step for rapidly freezing the rice after the water adding step again in a rose shape. It is said.

  The rice cooking step is a steaming step of steaming the raw rice, a hot water roasting step in which the raw rice after the steaming step is bathed in hot water of 80 ° C. to 100 ° C., and the raw rice after the hot water roasting step is equal to or less than the hot water temperature And a drying step of drying at a temperature of 5 ° C. Further, the water in the hydration step may be a seasoning liquid containing a seasoning, and may further contain one or more of polysaccharides, proteins and / or processed products thereof.

  In addition, in this invention, cooking raw material rice in the state from which gelatinization degree will be 80%-96% is cooking so-called rice to the half-life state with low gelatinization degree in the middle of cooking rice, and gelatinization degree is If it is lower than 80%, the rice is not completely cooked when the frozen cooked rice is thawed and heated, and if the degree of gelatinization is more than 96%, the rice is too soft when the frozen rice is thawed and heated.

  Moreover, the frozen cooked rice of this invention is obtained by the manufacturing method of the above-mentioned frozen cooked rice, The thawing method is characterized by carrying out the thawing | decompression heating in the pressurized state.

  Cook rice to a gelatinization degree of 80% to 96%, freeze it once in a rose shape, coat it with water, and then freeze it again to produce frozen rice. Therefore, when this frozen cooked rice is heated with thawing in a microwave oven, the frozen rice in a semi-lived state with a low degree of gelatinization is in a fully cooked state while absorbing the coated water, The cooked rice having the same texture, flavor and taste as the cooked rice can be obtained. In addition, during the thawing heating, the frozen cooked rice absorbs only the water coated around it, so that the water absorption amount of the rice grains after the thawing heating is stable, and the texture does not vary.

  Furthermore, after the rice having a low gelatinization degree is rapidly frozen in a rose shape, the texture, taste and flavor of the cooked rice can be freely arranged by coating the surface with various seasonings.

  By thawing and heating the frozen cooked rice obtained by the above-described method in a pressurized state, it is possible to obtain cooked rice having a more sticky and plump texture.

  FIG. 1 is a flowchart showing an example of a method for producing frozen rice of the present invention, and FIG. 2 is a flowchart showing an example of a conventional method for producing frozen rice.

As raw material rice, Koshihikari produced in Niigata Prefecture was used, and based on the flowchart shown in FIG. 1, frozen rice was produced by changing the temperature conditions for hot water and drying (experimental zones 1 to 5) as shown in Table 1. In addition, by changing the temperature conditions of the hot water bath and drying, adjustment was made by changing the hot water bath time and the drying time so that the water absorption rate of the rice before the primary freezing did not change.

  As shown in FIG. 1 and Table 1, first, in the rice washing step 11, the raw rice is poured into water at 15 ° C. and hand-washed rice that is stirred 20 times by hand is performed three times. The rice was immersed in water at 25 ° C. for 2 hours. In the steaming step 13, the raw rice after the dipping step was steamed for 12 minutes in atmospheric saturated steam using a home steamer.

  In the water bath 14, the raw rice after the completion of the steaming process is 6.5 minutes in 80 ° C. hot water in the experimental zone 1, 5 minutes in 85 ° C. hot water in the experimental zone 2, and 88 ° C. in the experimental zone 3. In the experimental group 4, it was poured into 94 ° C. hot water for 4.5 minutes, and in the experimental group 5, it was poured into 100 ° C. hot water for 4 minutes, and the water was roasted.

  In the drying step 15, using a steam convection oven, the test group 1 is 80 ° C. for 5 minutes, the test group 2 is 85 ° C. for 5.5 minutes, the test group 3 is 88 ° C. for 5 minutes, and the test group 4 is 94 ° C. For 5 minutes, and in Experiment Group 5 at 100 ° C. for 5 minutes, the cooked rice was heated and dried to obtain a half-lived cooked rice with a low gelatinization degree. In the cooling step 16, the cooked rice that had finished the drying step 15 was taken in a bowl or the like and cooled. The water absorption rate of the cooked rice after cooling was 93% in any experimental section with respect to the weight of the raw rice.

  In the primary refrigeration process (IQF) 17, the cooked rice after the cooling process and a cryogen such as snow-like dry ice, liquid nitrogen, and low-temperature air are put into a rose-shaped quick freezing apparatus equipped with a rotating drum. And the rice was freeze-frozen in a rose shape. In the hydration step 18, 20% by weight of water was sprayed and mixed with the rice that had been snap-frozen in the primary freezing step 17, and the surface of the cooked rice was evenly coated with water. In the secondary freezing step (IQF) 19, the water-coated rice was put into the rose rapid freezing apparatus again, mixed with a cryogen and rapidly frozen in a rose shape to produce frozen rice. The water content of the cooked rice after freezing was 132% in any experimental section with respect to the weight of the raw rice. In the packaging step 20, 120 g of the frozen cooked rice obtained in the secondary freezing step 19 was packed into a range-up bag.

  The frozen cooked rice thus obtained was thawed and heated for 2 minutes together with the bag in a 600 W microwave oven. As a result, the half-boiled cooked rice with a low degree of gelatinization in the frozen state is thawed at the same time, and it is completely cooked by heating, has a fresh texture and aroma, and has a good sticky taste I was able to get cooked rice.

  The range-up bag or container is preferably a bag of a type that can be pressurized and escapes steam when heated. For example, by applying pressure using a nylon-polyethylene laminate bag or a polypropylene container, the temperature during thawing heating can be set to 105 ° C. or higher, and the food is more sticky and plump. You can get a sense of cooked rice.

  Next, a conventional method for producing frozen cooked rice serving as the control section shown in Table 1 will be described based on the flowchart shown in FIG. The rice washing process 31, the dipping process 32, and the steaming process 33 in the control section were performed in the same manner as the rice washing process 11, the dipping process 12, and the steaming process 13 in the experimental sections 1 to 5 described above. In the hot water step 34, the raw rice after the completion of the steaming step was poured into hot water at 100 ° C. for 6 minutes for hot water. In the drying step 35, the raw rice after completion of the hot water roasting step was heated and dried at 100 ° C. for 12 minutes in a steam convection oven, and the raw rice was completely cooked. In the cooling step 36, the cooked rice was taken in a bowl or the like and cooled. The water absorption rate of the cooked rice after cooling was 132% with respect to the weight of the raw rice.

  In the freezing step (IQF) 37, the cooled cooked rice and the snow-like dry ice, liquid nitrogen, cryogen such as low-temperature air, etc. are put in and mixed in the rose rapid freezing apparatus equipped with a rotating drum, and the cooked rice is separated. It was snap frozen. The water content of the frozen rice after freezing was 132% based on the weight of the raw rice. The obtained frozen cooked rice was packed into a range-up bag in the packaging step 38. The frozen cooked rice thus produced was thawed and heated for 2 minutes together with the bag using a 600 W microwave oven.

Table 2 shows the results of thawing heating and comparing the quality of the frozen cooked rice in the experimental groups 1 to 5 and the control group obtained as described above.

  As shown in Table 2, the state after the thawing heating of the frozen cooked rice obtained in the experimental groups 1 to 5 is compared to the state after the thawing heating of the frozen cooked rice obtained in the control group. The taste was good.

  Comparing the state after the thawing heating of the frozen cooked rice obtained in the experimental groups 1 to 5, in the experimental group 1 in which the water bath temperature and the drying temperature were lowered, the degree of gelatinization was too low and even when heated during thawing The core was easily left in the center of the cooked rice, and the texture was not good. On the other hand, in the test sections 4 and 5 in which the hot water temperature and the drying temperature were increased, the stickiness of the cooked rice before the primary freezing was likely to occur, and lumps were easily generated after the primary freezing. From the above, under the condition that the water absorption before the primary freezing is 93%, and the water absorption by the spray after the primary freezing is 20%, the water bath temperature and the drying temperature conditions are 85 ° C to 100 ° C, preferably It turned out that what was set to 88 to 94 degreeC was favorable.

  Moreover, by drying the cooked rice at the same temperature as the bath temperature, the cooked rice was in a state where there was little adhering water on the surface and could be primarily frozen in a good state.

Using Koshihikari from Niigata Prefecture, as shown in Table 3, the temperature condition of the hot water bath and drying was fixed at 94 ° C. and the drying time was fixed at 5 minutes, and the time conditions of the hot water bath were changed (Experimental Zone 6, 7, 4 8), the quality of cooked rice obtained in the control group and each experimental group was compared. Each production condition is shown in Table 3, and the quality comparison result of cooked rice is shown in Table 4. In addition, the amount of water absorption of the rice before the primary freezing was changed by changing the time conditions for hot water and drying, and the amount of water added by spraying after the primary freezing was corrected, and finally after the secondary freezing. The water content was adjusted to be constant. In addition, the experimental group 4 of this example is the same as the experimental group 4 performed in Example 1.

  As shown in Table 4, the state after thawing heating of the frozen cooked rice obtained in the experimental plots 6, 7, 4 and 8 is all compared to the state after thawing heating of the frozen cooked rice obtained in the control plot, The aroma, taste and texture of the cooked rice were good.

  Comparing the cooked rice after thawing and heating obtained in the experimental plots 6, 7, 4 and 8, the longer the time of hot water roasting, the higher the water absorption rate of the rice before the first freezing, The feeling is improved and plump rice is obtained, but in terms of fragrance, the time of hot water roasting is shortened, and the lower the water absorption rate of the rice before primary freezing, the better. From the above, it was found that when the temperature condition of the hot water bath and drying is 94 ° C. and the drying time is 5 minutes, the hot water bath time is about 4.5 minutes.

Using Koshihikari from Niigata Prefecture and changing the water content after primary freezing as shown in Table 5 (experimental zone 9, 10, 3, 11), the quality of cooked rice obtained in the control zone and each experimental zone Compared. Each manufacturing condition is shown in Table 5, and the quality comparison result of cooked rice is shown in Table 6. In addition, the experimental group 3 of the present example is the same as the experimental group 3 performed in Example 1.

  As shown in Table 6, the state after thawing heating of the frozen cooked rice obtained in the experimental plots 9, 10, 3, and 11 is more fragrant than the state after thawing heating of the frozen cooked rice obtained in the control plot. And the taste was good.

  Comparing the states after thawing heating of the frozen cooked rice obtained in the experimental sections 9, 10, 3, and 11, the more the water content increased, the better the aroma and texture. On the other hand, in the experiment group 9 with a water content of 10%, even when heated at the time of thawing, the core tends to remain in the center of the cooked rice, and the texture is inferior. The water was not absorbed and remained around the cooked rice, and the resulting cooked rice became watery. From the above, it was found that under a condition where the water absorption rate of rice before primary freezing is 93% and the thawing heating time is 3 minutes in a microwave oven of 600 W, a water content of about 20% is good.

Using Koshihikari made in Niigata Prefecture, spraying several kinds of seasoning liquids after primary freezing and spraying on the surface of rice (Experimental area 12, 13, 14), and rice after spraying water after primary freezing The rice obtained in the experimental section 4 coated on the surface of the rice was compared. Each manufacturing condition is shown in Table 7. In addition, the seasoning liquid a used in the experimental section 12 was a solution obtained by slightly boiling an aqueous solution of 2.5% Hon Mirin and 1.5% sake, and the seasoning liquid b used in the experimental section 13 was washed with rice. After adding 500 g of water and 30 g of honey to 200 g of rice and leaving it to stand at 10 ° C. for 12 hours, the filtered liquid and the seasoning liquid c used in the experimental area 14 are bonito soup seasoning 1 g, salt 0.25 g, kelp soup seasoning A solution prepared by adding an appropriate amount of water to 30 g of a material, 10 g of soy sauce, 10 g of cooking liquor and 5 g of sugar and heating, and then adjusting the weight to 100 g by adding water was used.

  As a result, compared with the cooked rice obtained in the experimental group 4, the cooked rice obtained in the experimental group 12 has increased sweetness and a strong flavor overall. Compared with the cooked rice obtained in the experimental group 4, the cooked rice obtained in the experimental group 13 had a thicker adhesive layer on the surface of the rice and a good texture. The cooked rice obtained in Experimental Zone 14 had the same taste and texture as ordinary cooked rice.

  Thus, the texture, taste, and flavor of cooked rice could be freely arranged by using various seasoning liquids such as sushi vinegar as the liquid to be added after primary freezing. From the above, when producing frozen cooked rice industrially, it is possible to produce various products by adding various seasonings to cooked rice produced by the same manufacturing method until the first freezing. This is preferable because it makes it easier to produce frozen rice of other varieties.

  The liquid to be added may be polysaccharides, proteins, or processed products thereof. Examples of polysaccharides include starch degradation products such as starch syrup, gums such as pullulan and pectin, oligosaccharides such as raffinose, and proteins such as amylase. Examples of these processed products such as enzymes, gelatin and casein include bouillon, powdered milk, molasses and the like.

  Furthermore, the drying temperature for heating and drying the cooked rice after the hot water bath may be 1 to 2 degrees higher than the hot water bath temperature, or may be set lower than the hot water bath temperature.

The flowchart which shows an example of the manufacturing method of the frozen cooked rice of this invention The flowchart which shows an example of the manufacturing method of the conventional frozen cooked rice

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Rice washing process, 12 ... Immersion process, 13 ... Steaming process, 14 ... Hot water bath process, 15 ... Drying process, 16 ... Cooling process, 17 ... Primary freezing process, 18 ... Hydration process, 19 ... Secondary freezing process, 20 ... Packaging process

Claims (6)

On the surface of the cooked rice after the first freezing step, the rice cooking process in which the raw rice is cooked to a state where the gelatinization degree is 80% to 96%, the rice rice that has undergone the rice cooking process is rapidly frozen in a rose form, and A method for producing frozen cooked rice, comprising a water-coating water adding step and a secondary freezing step in which the rice after the water adding step is rapidly frozen in a rose shape. The rice cooking step is a steaming step of steaming the raw rice, a hot water roasting step in which the raw rice after the steaming step is bathed in hot water of 80 ° C. to 100 ° C., and the raw rice after the hot water roasting step is equal to or less than the hot water temperature The method for producing frozen cooked rice according to claim 1, further comprising a drying step of drying at a temperature of 5 ° C. The method for producing frozen cooked rice according to claim 1, wherein the water in the hydration step contains a seasoning. The method for producing frozen cooked rice according to claim 1, wherein the water in the hydration step contains one or more of polysaccharides, proteins and / or processed products thereof. Frozen cooked rice obtained by the production method according to any one of claims 1 to 4. A method for thawing frozen cooked rice, comprising: thawing and heating the frozen cooked rice obtained according to claim 5 in a pressurized state.

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